What kind of spider almost killed me?
August 30, 2007 4:01 PM   Subscribe

A spider landed on me in Hawaii. It was very big (almost palm sized), and black with yellow and blue splotches on it. Is it poisonous?

I went on a horseback ride in Hawaii over a year ago. In particular, it was in Kona pretty much between North and South Kona by the Kealakekua Monument. As we walked along (obviously the horses did the walking), I enjoyed the flora and fauna of the Big Island. I saw spiders--big spiders. They were were big (not quite like a Buick), and black with yellow and blue splotches (UCLA colors). As we walked, I saw a spider descending on its thread. As I got closer, I thought, "That thing's going to land on me." And sure enough, it landed on my shoulder.

I felt a great sense of panic that can't even be described by using the word 'panic.' I thrashed, yelled (okay, screamed), and hit at the spider. I yelled, "Get it off me! Get it off me!" as well as a variety of expletives. I hit it off onto my leg. It crawled up my leg, and I kept hitting at it. It landed on the saddle, climbed up on my leg again, and I finally knocked it off. I lost my sunglasses during the struggle, but that's besides the point.

The trail guide asked what happened, and I told him a spider landed on me. I described it, and he said, "Oh, those? My little daughter plays with those. They're harmless."

So for a long time, I thought, "I'm such a dork. I wasn't in any danger." I recently told someone that story, and they said, "I don't know...Brightly colored spiders are usually brightly colored for a reason. You know, because they're poisonous and their colors are supposed to warn predators." We all feel pretty smart after watching the National Geographic channel, but maybe there was some truth to that.

I got to thinking that maybe the trail guide was saying that the spider was harmless to calm me down, and perhaps make me think I was over-reacting, when in fact I had been in grave danger. It wouldn't help business any if word got out that his horseback rides were potentially fatal.

So based on what happened and the description of the spider, can you help me figure out what kind of spider it was and if I was about to die?
posted by rybreadmed to Pets & Animals (15 answers total) 1 user marked this as a favorite
This spider is harless.
posted by Crotalus at 4:12 PM on August 30, 2007

No. You probably saw a Nephila or an Argiope, and theyre brightly coloured because current thinking indicates that the colours actually attract prey to the web. Maybe you would have died of a panic attack and/or falling off your horse.
posted by dhruva at 4:17 PM on August 30, 2007

Hawaii has cane spiders and banana spiders, as well as brown recluse and black widows. Black widow spiders are not large and have a red distinct hourglass marking on their backs. Brown recluse spiders are, as their name implies, not at all ostentatious in coloring or appearance. Cane spiders are large, but light brown.

It seems, then, that you might have been bitten by a banana spider (also called a writhing spider). They are large and black with bright yellow blotchy coloring. I have not heard of the bluish coloration, however.

If it were a banana spider, it would not be the Central and South American variety, which ARE poisonous. As for the Hawaiian (North American) variety, they look alarming, but their bite, for anyone who does not have an allergic reaction to spider bites, is no worse than a bee sting. They actually have a small amount of venom similar to that of a black widow, but it is very diluted in comparison, so that it is virtually harmless to humans.

The best pic I could find of a banana spider is on this website.
posted by misha at 4:20 PM on August 30, 2007

Response by poster: So it seems to be exactly as I originally thought: I'm a weenie and panicked for nothing.
posted by rybreadmed at 4:43 PM on August 30, 2007

Nah: it's an instinctive reaction.
posted by dhruva at 5:56 PM on August 30, 2007

Thank you for posting this. Now I know I never want to go to Hawaii.

posted by konolia at 6:11 PM on August 30, 2007 [3 favorites]

Fear of spiders is much more likely to kill or maim you than spiders are (consider the freeway driving + spider drops from sunshade scenario). It's worth fixing.
posted by flabdablet at 10:07 PM on August 30, 2007

Are you dead yet?
posted by rcavett at 10:49 PM on August 30, 2007

This spider is harless.

Yep. Completely devoid of har.
posted by davejay at 11:39 PM on August 30, 2007 [1 favorite]

With regards to your second point, the reason for bright coloring is not always to warn predators. Bright colors can evolve as a result of sexual selection (think of the peacock) and even when they are meant to warn predators you may be seeing an example of Batesian mimicry whereby such patterns may be copied by a non-poisonous organism to acquire protection.
posted by kepano at 2:04 AM on August 31, 2007

Ha, ha. Your question reminded me of a date I went on when I lived on Guam. Most beautiful girl I've ever seen; I somehow convinced her to go on a jungle hike with me. Walking along, chatting, I walked right into a web of one of the spiders I think you're describing. I screemed like a 6 y/o girl and swatted the air like an epilectic until I fell down. She laughed her ass off and never went out with me again.

Yeah, they're totally harmless (to your body, but they'll tear the fuck out of your ego)
posted by Pecinpah at 3:59 AM on August 31, 2007

(...and sorry for the chatty answer, but I find succor in shared humiliation)
posted by Pecinpah at 4:03 AM on August 31, 2007

Teleological and theological arguments aside, it's wrong to think that biological traits exist for a reason, and that some traits (like color) infer other unrelated traits (like poisonous bites).

Mutation and selection don't aim at goals. Things mutate randomly all the time, and the only way mutations go away in subsequent generations is if they lower the critters' chance of survival or reproduction.

Now, the color=poison idea probably comes from the idea that if you're colorful, then you're likely to be seen and be eaten by a predator. The only populations that can survive becoming colorful are those that are already poisonous to eat.

But, in this case, that assumes that
1) there is a predator on that island, and
2) the critter uses the "being eaten poison" as a "eater venom".

You can witness the number of times eater vs eaten poisons are different. Birds eat rattlesnakes all the time. The blowfish doesn't use its poison to attack. Those deadly tree frogs don't stun bugs with poison.

Of course, this argument never means much when something ugly drops on your neck and your glands dump a quart of adrenaline into your bloodstream.
posted by cmiller at 6:38 AM on August 31, 2007

While it's true that bright colors can serve as a warning to predators (Müllerian mimicry), the coloring is not necessarily about advertising an ability to deliver a dangerous sting or bite. It could warn that the animal tastes bad or would make a predator sick. Colors can also be a type of camouflage-- hiding rather than advertising. That's the more likely case for the spider. If you search for medically significant spiders on the internet, you'll notice that generally they're fairly drably colored. You can't really predict which spiders might be dangerous based on brightness of the coloring. The good news is that the vast majority of spiders do not have venom that is dangerous to humans.

Perhaps the most common explanation for many of the color patterns exhibited by spiders is for avoidance of predation (Foelix 1982). Spiders can use color to hide from (crypsis) or confuse predators (Oxford and Gillespie 1998); here color is generally associated with a specific habitat.

-- Portraits of Evolution: Studies of Coloration in Hawaiian Spiders [PDF article]
posted by Tehanu at 8:24 AM on August 31, 2007

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